In the production of individual pieces from a continuous extrudate rope, efforts have been made to form individual pieces which are both regular and uniform, and at the same time which do not leave a high percentage of waste or scrap material. For example, in forming individual pieces from a single extrudate rope, it is known to simply stamp the rope with a die having the shape of the article desired therein. Although somewhat successful, this practice generally results in a relatively high percentage of waste or scrap of the extrudate rope. Due to sticking of small bits of extrudate to the die, it is difficult to maintain perfectly uniform output piece shape and size during production.
In another type of cutter, shown in copending application U.S. Ser. No. 06/507,401, filed 6-24-83, an extrudate rope is cut into pieces leaving generally triangular pieces of scrap. The extrudate rope may be formed with a core of a first composition, and an outer layer of a second composition. In the aforesaid application, two curved blades are employed in cutting the extrudate rope, however the volume between opposing pairs of the blades is left open so that generally triangular pieces of scrap will remain after cutting. Where the volume between each pair of blades is filled in, the inner dough of the extrudate, which may be of a different composition than the outer dough portions, is squeezed away from the scrap portions and toward the central portions of the pieces to be formed. Thus, the triangular scrap portions are substantially composed of the outer layer, and not the core composition; however, in the case where the core material has the particulate matter or chip pieces is not squeezed away from the scrap pieces, but rather remains with the scrap.
The present invention eliminates the need for use of the "rubber dam" type of apparatus. In that type of apparatus, an extrudate travels beneath a reciprocating die head. A rubber sheet or dam is tensioned between two rollers, and is disposed between the extrudate rope and the die head. During operation, the rubber sheet induces release of extrudate rope pieces from the die head, since as the die head moves upward the extrudate rope pieces are contrained by the rubber dam to remain with the conveyor belt and not be taken up with the die. This apparatus has the disadvantages of requiring reportioning of the rubber dam at very frequent intervals, and results in a relatively "messy" operation due to spreading and scattering of the extrudate rope.
In co-pending application U.S. Ser. No. 06/540,983, filed 10-11-83, shims are used, underlying portions of a die head during stamping. This causes dough to be squeezed toward the hollow portions of the mold, used to form the pieces, and thus minimize scrap losses.
In stamping of an extrudate rope, waste occurs during stamping due to spreading of the extrudate rope while under pressure by the die. Thus, portions of the extrudate rope will flow beyond the regions desired for formation of a regular article. Although it is known in the prior art to recover such scrap and attempt to reuse it, this is not always satisfactory.
Recycling of scrap pieces of extrudate rope in the food industry, for example, may be objectionable in cases where the extrudate toughens with exposure to air or otherwise becomes unsuitable for reuse in the stamping operation. Also, where the extrudate rope is formed of two or more materials arranged in different regions to achieve a specific resultant product, recycling of scrap pieces is completely unsatisfactory because such scrap will generally be of a mixture of materials which cannot readily be separated for reuse in an appropriate manner. For example, an extrudate rope may be a cookie dough having an inner core of one type of dough having a first predetermined property with an outer layer surrounding the inner core of a different dough material having a second predetermined property. Thus, scrap pieces generally cannot be recycled from an extrudate rope of this type.
In the prior art stamping operation of Ser. No. 06/507,401, filed 6-24-83, described above, wherein each individual piece is stamped and formed by two opposing blades of the die in a two-stroke operation, highly regular pieces are formed.
It is desirable in any stamping operation that a large number of pieces be formed from an extrudate rope in a minimum amount of time, both to conserve labor costs as well as to conserve floor space taken up by equipment used in the manufacture of such pieces. It is therefore desirable that a plurality of extrudate ropes by operated upon by a single machine simultaneously, thereby permitting a single operator to tend to such machine and for such machine to be arranged in a compact manner to conserve floor space.
In U.S. Pat. No. 3,205,837, issued to R. J. Fay, sintered porous bronze is used to form a die. The die is used in a rotary die roll to produce dough pieces. A low pressure fluid passes through the sintered die to create a film of fluid between the articles and the die. Reference is made to Teflon.RTM. dies or die portions in col. 1 at lines 25,30. No bores are used, however, to provide air directly to the die.
Another type of rotary mold for food products is taught in U.S. Pat. No. 3,427,649, also to Fay. Here also, air is forced through porous die walls to assist in separation of the food products from the die.